Mesh structure and laminate made therewith

ABSTRACT

In order to produce a biaxially orientated mesh structure using a single axis draw, a plastics material starting material has parallel, side-by-side main zones separated by lines of holes or depressions; the starting material is drawn parallel to the main zones, stretching the main zones into continuous, orientated main strands 4 interconnected by smaller cross-section strands 6 which have been formed from the zones between holes or depressions in each line, and have been orientated at right angles to the direction of drawing by the effect of the main zones decreasing in width as they were stretched. The mesh structure is suitable for cross-lamination.

This is a divisional of application Ser. No. 765,186 filed 8/13/85, nowU.S. Pat. No. 4,618,385 which in turn is: a Rule 62 continuation ofapplication Ser. No. 510,252 filed July 1, 1983, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of making a mesh structure,comprising providing a starting material which has substantiallyparallel lines of holes or depressions defining elongate, side-by-sidemain zones between the lines of holes or depressions and intermediatezones between the holes or depressions in each line, and drawing thestarting material in a direction substantially parallel to the mainzones to stretch the starting material out into a mesh structure havingorientated main zones with the orientations therein extending generallyparallel to the drawing direction.

2. Description of the Related Art

GB No. 2 073 090B discloses such a method, used for makinguniaxially-orientated structures, and GB No. 2 035 191B disclosessimilar starting materials, being stretched in two directions at rightangles to form biaxially-orientated structures, GB No. 2 073 090B and GBNo. 2 035 191B can also be referred to for background details onstretching and orientating plastics materials.

In the uniaxially-stretched materials of GB No. 2 073 090B, the parts ofthe main zones which are directly between holes or depressions stretchout, forming strands interconnecting bars which comprise the remainderof the main zones and also the intermediate zones. In order to obtainbiaxial orientation, the structure must be stretched in the direction atright angles, as set out in GB No. 2 035 191A.

U.S. Pat. Nos. 3, 906,073, 3,719,540 and 3,500,627 disclose productswhich apparently have main, orientated strands with the orientationtherein extending from end to end. In each case, the main strands areinterconnected at a plurality of positions spaced along the main strandsby orientated fibrils which, at least in the case of the first two USSpecifications, branch out from the main strands at a small angle.

SUMMARY OF THE INVENTION

It is desirable to be able to produce a biaxially-orientated structurewith a single direction stretch. The structure so produced should becapable of having two clear axes, substantially at 90° to each other,though this may not be necessary in all circumstances. Thus it should bepossible to have the orientated interconnecting strands substantially atright angles to the main strands, and certainly making a large angle tothe main strands.

Definitions

The term "rectangular" includes square.

The term "orientated" means molecularly orientated.

The term "thickness" refers to the dimension normal to the plane of thestarting material or mesh structure, the term "width" refers to theappropriate dimension in the plane of the starting material or meshstructure (normally at right angles to the direction of the strand inquestion), and the term "w:d ratio" is the ratio of the width to thethickness.

The "calculated stretch ratio on the interconnecting strands" is theratio of the distance apart of the mid-points of the main zones afterdrawing to that before drawing (though normally the actual stretch ratiois less due to the main strands necking down slightly between connectionpoints with the interconnecting strands).

The width of a main zone is generally the distance between the two lineswhich are tangent to the line of holes or depressions on either side ofthe main zone, the same being the case mutatis mutandis for main strandsand mesh openings. A somewhat different definition applies to a ribbedstructure (see below).

The depressions are not necessarily formed by the application ofpressure.

In the method of the invention, the starting material has substantiallyparallel lines of holes or depressions defining elongate, side-by-sidemain zones between the lines of holes or depressions and intermediatezones between the holes or depressions in each line. The startingmaterial is drawn in a direction substantially parallel to the mainzones while preventing substantial contraction in the direction at rightangles to the drawing direction, thereby stretching the main zones outinto orientated main strands with the orientation therein extending fromend to end and generally parallel to the drawing direction, decreasingthe width of the main zones when forming the main strands, andsimultaneously stretching the intermediate zones between the main zonesin a direction at a large angle to the direction of drawing, whereby, inthe mesh structure produced, orientated interconnecting strands, formedfrom the intermediate zones, interconnect the main strands, with theorientation in the interconnecting strands extending at a large angle tothe main strands.

In the mesh structure of the invention, there are parallel, orientatedmain strands whose orientation extends from end to end thereof andgenerally parallel thereto, and orientated, interconnecting strandsinterconnecting the main strands, the interconnecting strands extendingat a large angle to the main strands and having orientation which isdirected generally parallel to the interconnecting strands. The meshstructures can be used to form laminates, particularly cross-laminateswith the main strands of one mesh structure layer generally at rightangles to the main strands of another mesh structure layer.

In the method of the invention, the main, parallel zones narrow down toform the main strands and thus stretch out the subsidiary intermediateor traverse zones into orientated interconnecting strands whoseorientation is preferably at right angles to the direction of drawing,and calculated stretch ratios of 5:1 or more can be applied to theinterconnecting strands. The orientation of the main strands extendsfrom end to end thereof although they are interconnected by theinterconnecting strands at a plurality of positions spaced along themain strands.

It has thus been discovered that a mesh structure which has substantialorientation in two directions at right angles can be produced bystretching a substantially unorientated starting material in a singledirection. Nonetheless, as explained below, the invention is notrestricted to using a single, unidirectional draw.

To facilitate the stretching of the "traverse" zones, these zones shouldnot be too wide (i.e. should not have too great a dimension in thedirection in which the main zones are stretched)--they are preferablysubstantially narrower than the main zones, e.g. one quarter the widthor less, i.e. the distance between the holes or depression of one lineand those of the adjacent line being at least four times the distanceapart of the holes or depressions in any one line. The main strands canhave a uniform thickness along their centre line (or another lineparallel to their axes) and their width can also be fairly uniform.These main strands run right through the mesh structure and give themesh structure its strength. Particularly if the mesh structure is beingused for a cross-laid laminate (main strands of one mesh structure layergenerally at right angles to the main strands of the other meshstructure layer), the transverse strength of the mesh structure is notof importance and need only be sufficient for machine handling in anautomatic process; the interconnecting strands need only to keep themain strands roughly parallel prior to laminating. However, it isundesirable to stretch the main strands to such a degree that theyfibrillate (if this is possible with the particular plastics materialused).

It is believed that if the main zones or strands are to exhibitsufficient strength to orientate the intermediate zones, theinterconnecting strands should be of smaller cross-sectional area thanthe main strands, and those cross-sectional areas are convenientlymeasured at the mid-points. The main strands can predominate in weightper square unit area of the mesh structure, for instance forming 85, 90,95% or even more of the weight of the product, thus ensuring economicuse of the plastics material.

In order to achieve this, and in order to achieve goodcross-orientation, the distance between the main zones can be small(i.e. the main zones being close together), the holes or depressions (ifpresent) being correspondingly small and forming a very low percentageof the surface area of the starting material. Apart from the foregoing,a small distance between the main zones (when the main zones are closetogether) can give good cross-orientation. A small percentage widthreduction of the main zones can give a large stretch ratio on theintermediate or transverse zones. The main zones in the startingmaterial are preferably at least two or four times as wide as thedistance between such zones, it appreciable stretch is to be achieved inthe interconnecting strands. There would be a large number of theside-by-side main zones, e.g. at least ten and preferably at least fiftyor a hundred. Mesh structures can be produced with from fifty to fourhundred main strands to the meter and one would expect mesh structurewidths of one to four meters. The main strands will usually be ofsubstantially rectangular section, i.e. two sides of the rectangle beingthe faces of the mesh structure.

If the starting material is to be drawn solely in the transversedirection (TD), a stenter can be used. In general, the holes ordepressions in each line should be close together to achieve the crossorientation of the intermediate zones--the intermediate zones would thusbe small, as measured in the direction in which the starting material isdrawn.

Though one can use a single, unidirectional draw, it may be possible oradvantageous to draw the starting material biaxially. Thus the startingmaterial can be drawn, e.g. to a small stretch ratio, in the directionat right angles to the main zones. This drawing will orientate theintermediate zones to a certain extent, through the orientation need notpenetrate into the sides of the main zones (i.e. pass beyond notionallines on either side of a respective main zone and tangent to the holesor depressions). The stretch ratio on the interconnecting strands soformed may be for instance 2:1. Subsequently (or even possiblysimultaneously), the material is drawn parallel to the main zones,stretching out the main zones but also further stretching out theinterconnecting strands in a direction parallel to their axes. The wholeoperation could be performed by giving a small machine direction (MD)draw using draw rolls and then giving a large TD draw in a stenter.

As a further possibility, once the main strands have been formed, it ispossible to draw in the direction at right angles to the main strands,further to stretch out the interconnecting strands, possibly reducing oreliminating the thicker small zones referred to below.

In general, in the mesh structures of the invention, the ratio of mainstrand width: transverse pitch of main strands, as measured atmid-points (which are usually the narrowest points) of the main strands,is preferably below 1:5, say from 1:4.5 or 1:4.25 or 1:4 down to 1:2,though larger relative transvese pitches are possible with suitabledimensioning of the starting material--the main strands at theirnarrowest points may be separated by a distance of not more than threetimes their width at their narrowest points.

The production of the correct mesh structure depends upon a combinationof various parameters, such as pitching of the holes or depressions(i.e. transverse dimension of the individual intermediate zones andwidth of main zones) and draw ratio applied to the main zones. The mainzones in the starting material and the main strands in the meshstructure are preferably much wider than they are thick and hencetape-like, preferred w:d ratios for both the main zones and the mainstrands being at least about 5:1, or at least about 10:1, or at leastabout 20:1. If the main zones are not very close together, high w:dratios are required. The actual thickness, if uniform, may not be ofgreat importance, though this has not been assessed experimentally. Itis found easier to obtain more uniform thickness strands with very thinstarting materials, the thickness normally becoming less uniform as theaverage thickness increases (i.e. less thickness difference between mainstrands and the interconnecting strands, and between different zones inthe structure); it is found that starting materials of thickness of 0.5mm and less are preferred, the most useful being those of 0.2 mm andless. However, in principle, the starting material can be of anysuitable thickness.

The preferred starting material is strictly uniplanar, by which is meantthat, ignoring any membrane (which may not lie on the median plane), allparts of the starting material are symmetrical about the median plane ofthe starting material; in this manner, in the mesh structure, all partswill be symmetrical about the median plane, ignoring any membrane, filmor fibrils (which may not lie on the median plane) produced from thestarting membrane. It is further preferred that the starting materialshould have planar faces apart from the holes or depressions. Howeverinsubstantial departures from uniplanarity or from planarity are notexcluded--for instance, in an alternative to having starting materialwith planar faces, it would be possible to provide the starting materialwith parallel ribs, which could be formed by direct extrusion orembossing, the ribs forming the main zones (in this case, the width of amain zone is the width of the rib).

The holes (or depressions if applicable) can be formed e.g. by punching,slitting, embossing or burning in (on a water-cooled roller), or byforming them as the starting material itself is formed (for instanceobturating a slit die e.g. generally as in French Patent SpecificationNo. 368 393 or by integral extrusion of a square mesh as in U.S. Pat.No. 3,325,181). Slitting is a useful way of forming the holes as thereis no substantial material removal and as it enables the main zones tobe very close together. A useful process is that in which a plasticssheet is formed with longitudinal slits, and is then heated whilst itslongitudinal margins are restrained, forming roughly elliptical holes.In general, it is preferred to avoid any substantial protuberance aroundthe periphery of the holes or depressions. If depressions are formed,the membrane closing the depressions can be ruptured during stretchingand the residual film-like material removed; alternatively, anorientated film can remain in the mesh openings.

The starting material is preferably not substantially orientated, thoughmelt-flow orientation can be present.

The starting material can be any suitable thermoplastics material, suchas for instance high density polyethylene (HDPE), low densitypolyethylene, polypropylene, copolymers of HDPE and polypropylene,polyesters, and polyamide. Tape-like filaments tend to crack or splitwhen produced from some plastics such as HDPE and polypropylene, butthese may be acceptable for certain uses--the use of polyesters canreduce the tendency to crack or split. The starting material can have askin on one or both faces containing an ultra-violet stabiliser; if alaminate is formed and the skin is on one face, it would be on theoutside face.

The intermediate zones are stretched (and hence usually the axes anddirection of orientation of the interconnecting strands will extend) ata large angle to the direction of drawing the starting material; thisangle is preferably roughly 90°, but the angle could be substantiallyless than 90° though it is preferably more than 75°. Thus, though theinterconnecting strands preferably extend substantially at right anglesto the main strands, this need not be so; the interconnecting strandsneed not have any specific geometrical shape nor be aligned with anyinterconnecting strand on the other side of the respective mainstrand--for instance, the interconnecting strands could form the"verticals" in a "brick wall" pattern with the main strands forming the"horizontals".

The mesh structure can be very flat and thus easily laminated to providegood cross-laid laminates. Although there may be small zones of thickerand unorientated or less orientated material where the interconnectingstrands join the main strands, there need be no large-sized noduleswhich could interfere with bonding. The structure may be cross-laminatedwith a similar or identical structure, but this is not necessarily so.The structures can be bonded directly face to face or can be separatedby at least one further layer.

The mesh structure of this invention can have a high strength in thedirection of the main strands and thus the cross-laid laminate will havegood strength characteristics in two directions at right angles. As themesh structure of the invention can be formed and laminated at muchgreater speeds than fabrics can be woven or knitted, the inventionrenders possible the fabrication at relatively high speeds of a materialwhich can be substituted for woven fabrics for some purposes.

The mesh structure of this invention can be used without lamination,i.e. as an unlaminated material.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a plan view of a plastics starting material for forming a meshstructure in accordance with the invention;

FIG. 2 is a plan view of the mesh structure formed therefrom;

FIGS. 3 and 4 are plan views of two further mesh structures inaccordance with the invention;

FIG. 5 is a perspective view of the mesh structure of FIG. 4;

FIG. 6 is a section along the plane VI--VI in FIG. 5;

FIG. 7 shows various shapes of holes or depressions that can be used inthe starting material;

FIG. 8 is a schematic perspective view of a laminate in accordance withthe invention; and

FIG. 9 to 14 are schematic sections through six other laminates inaccordance with the invention.

In the drawings, the hatchings run up and down the slope; only samplecontoured zones are indicated with hatchings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 5

Looking at FIG. 1, the starting material is a sheet of plastics material1 having planar faces and in which are formed lines of holes ordepressions 2, the holes or depressions 2 in each line being closetogether and dividing the starting material 1 into a large number ofparallel main zones 3 which are close together and on either side of orseparated by the lines of holes or depressions 2. The holes ordepressions 2 preferably have their centres on a notional rectangulargrid and the area of the holes or depressions 2 is preferably less than20% of the plan view of the starting material 1. For the purposes ofillustration and for most of the following Examples, the holes ordepressions 2 are shown as circular, but Figure 7 shows various shapesfor the holes or depressions 2, including simple piercings and slits.Although circular holes or depressions are easier for tooling, it issuggested that square holes on the square, with radiussed corners (FIG.7, middle of top row) give better control during stretching and abetter, more regular product--"on the square" means that the sides ofthe square are parallel to and at right angles to the stretch direction.If elongated, the direction in which the major axis of the hole ordepression 2 extends can be either parallel to the lines of holes ordepressions 2 or at right angles thereto.

The starting material 1 is drawn only in the direction indicated by thedouble arrow in FIG. 1, while preventing any substantial contraction ofthe web of material as a whole in the direction at right angles to thedrawing direction. The main zones 3 in the starting material 1 arestretched out into orientated, rectangular section main strands 4 (FIG.2) which are like tapes or filaments running right through thestructure, their orientation extending longitudinally thereof and fromend to end thereof and their centre lines having substantially uniformthickness. At the same time, the width of the main zones 3 decreases;the small transverse or intermediate zones 5 between the main zones 3and between the holes or depressions 2, are stretched at right angles tothe direction of drawing, to form smaller cross-sectional area,orientated, transverse, interconnecting strands 6 interconnecting themain strands 4 at a plurality or large number of positions spaced alongthe main strands 4, with the orientation extending longitudinally of theinterconnecting strands 6, i.e. at right angles to the drawingdirection. In the generally rectangular mesh openings formed, the largesdimension parallel to the main strands 4 is substantially greater thanthat at right angles to the main strands 4. The width of theinterconnecting strands 6 is substantially less than that of the mainstrands 4 whilst the orientation of (or stretch ratio applied to) theinterconnecting strands 6 may be substantially more than that applied tothe main strands 4, though this is not essential. The stretch ratio ofthe interconnecting strands 6 is determined by the diameter or width ofthe holes or depressions 2 and the reduction in width of the main zones3 when forming the main strands 4. The main zones 3 should decrease inwidth by at least 50%, as measured at their narrowest parts. Accordingto the stretch ratio applied, small thicker zones 7 (small blobs and/orunstretched shoulders) may remain adjacent each end of eachinterconnecting strand 6. The zones 7 may be thicker than both the mainand interconnecting strands 4,6, or just thicker than the main strands4. The zones 7 need not necessarily be present; for instance withpolyester, the corresponding zones may be flat or have slightdepressions, indicating that biaxial orientation has occurred in suchzones (this possibly occurs even if there are blobs or shoulders). Noaccount is taken herein of the small zones 7, or of the depressions,when giving the stretch ratios on the interconnecting strands 6, i.e. itis assumed that the whole of each interconnecting strand 6 stretched outuniformly, although this may not be the case.

The stretching is carried out at a temperature (glass transistiontemperature) above the second order transition temperature of theplastics material but substantially below the softening point so thatmelt flow orientation is avoided during the stretching; for example forHDPE, the preferred temperature range is 75° to 102° C. Afterstretching, the structures can be annealed in a well known manner.

FIG. 7

As indicated above, FIG. 7 shows various shapes of holes or depressions2 that can be used in the starting material.

EXAMPLES

To provide typical examples, a parallel-faced starting material wasformed with holes on a notional rectangular grid. The square holes ofExample 4 were "on the square".

The starting material was stretched at an elevated temperature. Thefollowing Table gives details of four Examples. All dimensions are inmm, unless otherwise specified. The starting material was planar andeffectively parallel sided, though differences in thickness were notedin one starting material (used for Examples 1 and 2), the maximum andminimum thickness of the starting material being recorded as 0.28 and0.21 mm (nominal 0.25 mm). In each Example, the maximum thickness of theproduct was at zone 7. Due to thickness variations in the startingmaterials (small in the case of Examples 3 and 4), there were variationsin the dimensions observed in the products, but average values have beenrecorded for Examples 1 and 2 and typical values for Examples 3 and 4.In commercial production, closer thickness tolerances would be requiredof the starting material than those indicated for Examples 1 and 2.

                  TABLE                                                           ______________________________________                                        Example      1        2        3      4                                       ______________________________________                                        FIGS. in which                                                                             2        3        4      4**                                     illustrated                                                                   Material     80/20         HDPE     HDPE                                                   HDPE/LDPE*                                                       Thickness    0.25          0.5      4.5                                       Hole shape   circular circular circular                                                                             square,                                                                       radiussed                                                                     corners                                 Hole size    1.6      3.175    1.6    6.35                                                                          0.75                                                                          radius                                                                        corners                                 Hole pitch   2.4      4.7      2.4    8                                       (stretch direction)                                                           Hole pitch   6.36     12.7     12.7   25.4                                    (transverse)                                                                  w:d ratio main zones                                                                       19:1     38:1     22:1   4.2:1                                   Temperature of                                                                             75-85    75-85    90     96                                      Stretching (°C.)                                                       Stretch ratio on                                                                           7:1      3.5:1    9:1    5.6:1                                   longitudinal strands                                                          Longitudinal strand                                                                        66%      38%      44%    53%                                     width reduction                                                               (measured at                                                                  mid-point)                                                                    Maximum opening                                                                            4.9      7.2      6.5    15.5                                    size, measured in                                                             transverse direction                                                          Calcalated stretch                                                                         3.03:1   2.26:1   4.06:1 2.58:1                                  ratio on inter-                                                               connecting strands                                                            Longitudinal strand                                                                        0.08     0.07     0.16   1.78                                    thickness (mid point =                                                        thinnest point)                                                               Longitudinal strand                                                                        1.5      5.5      6.2    9.0                                     width (mid-point =                                                            narrowest part)                                                               w:d ratio longi-                                                                           19:1     79:1     39:1   5:1                                     tudinal strand                                                                Interconnecting                                                                            0.08     0.07     0.20   2.5                                     strand thickness                                                              (mid-point)                                                                   Interconnecting strand                                                                     0.3      0.3      0.5    1.0                                     width (mid-point)                                                             Thickness of thickest                                                                      0.18     0.18     0.45   3.3                                     point of structure                                                            ______________________________________                                         *Co-extrusion (onesided)                                                      **Closest FIG.                                                           

FIG. 8

A cross-laid laminate is shown in FIG. 8, and can be considered ashaving been made in a machine whose machine direction (MD) is indicatedby the arrow. The laminate is formed of two layers 21, 22, each of whichcan be generally in accordance with any of FIGS. 2, 3, or 4. The toplayer 22 has been stretched in the MD and the bottom layer 21 has beenstretched in the transverse direction (TD).

The bonding is preferably effected by providing a multi-componentstarting material, having on at least one face a bonding material whichbonds at a temperature which does not destroy the physical properties ofthe mesh structure, the two mesh structure layers being heated to bondthem--thus the bonding material can be a skin which melts or becomestacky at a temperature (or temperature and pressure) at which the maincomponent of the mesh structure would not de-orientate. The bondingmaterial may be for instance ethylene vinyl acetate or low densitypolyethylene (LDPE); the starting material can for instance beunorientated 0.15 mm thick polypropylene with a thin layer of LDPE on atleast one face. The bonding material can be provided in any suitableway, for instance by extrusion coating or co-extrusion. Alternatively, abonding material or adhesive can be applied immediately prior tolaminating.

FIGS. 9 to 14

In FIGS. 9 to 14 MD stretched layers are indicated as 21 and TDstretched layers are indicated as 22, although in the alternative thesecould be reversed. FIGS. 9 and 10 illustrate three-layer and four-layerlaminates respectively. FIGS. 11 to 13 shows the incorporation of one ormore layers 23 of another material, e.g. polyethylene film. FIG. 14shows the lamination of a layer which can be generally in accordancewith FIG. 2, 3 or 4, with a film 23 of plastics material, e.g.polyethylene film, which has a preferred or single direction oforientation (direction of maximum strength) at right angles to the mainstrands 4.

Uses

The single layer mesh structure of the invention can be used for:Sunshade cloth, wind-breaks, sand barriers (small thicknesses), civilenginerring such as ground stabilisation or reinforcement (largethicknesses), general construction, such as concrete reinforcement,plaster reinforcement for ceiling panels or as a false ceiling, andasphalt reinforcement with the main strands extending transversely ofthe traffic direction (in this case, polyester is a preferred material).

The laminate of the invention can be used for or as an alternative to:

Textile fabrics for industrial application, wind-breaks, shade cloths,bases for needle felt, olive harvesting nets, packaging, tarpaulin, balewraps, carpet backings, or sacks or bags e.g. for wool, cement(laminated with paper or film) or fertilizers.

I claim:
 1. An integral, biaxially-molecularly-orientated meshstructure, comprising:continuous, substantially parallel,molecularly-uniaxially-orientated main strands with the orientationtherein extending substantially uniformly from end to end and generallyparallel to said main strands, said main strands being of substantiallyrectangular cross-section with their width substantially greater thantheir thickness; and discontinuous, uniaxially-molecularly-orientatedinterconnecting strands with the orientation therein extending generallyparallel to the direction of said interconnecting strands, saidinterconnecting strands extending in a direction generally at rightangles to said main strands and interconnecting said main strands at aplurality of positions spaced along the edge of each said main strand,each said interconnecting strand being generally symmetrical about aline at right angles to said main strands, to thereby define a generallyregular mesh structure having generally four-sided mesh openings, eachsaid mesh opening being defined by two said main strands and two saidinterconnecting strands, and the cross-sectional area at the mid-pointsof said interconnecting strands being less than the minimumcross-sectional area of said main strands; there being adjacent each endof each said interconnecting strand a zone of plastics material which isthicker than the material of the remainder of the respective saidinterconnecting strand.
 2. The mesh structure of claim 1, wherein saidplastics material zones are substantially unorientated.
 3. The meshstructure of claim 1, wherein said plastics material zones are lessorientated than the material of the remainder of the respective saidmain strand.
 4. The mesh structrue of claim 1, wherein said plasticsmaterial zones are less orientated than the material of the remainder ofthe respective said interconnecting strand.
 5. The mesh structure ofclaim 1, wherein the major part of the thickness of each saidinterconnecting strand is between planes defined by the outer faces ofsaid main strands.
 6. The mesh structure of claim 1, wherein the medianplane of each said interconnecting strand is substantially on the medianplane of said main strands.
 7. The mesh structure of claim 1, whereinthe median plane of each said interconnecting strand is between planesdefined by the outer faces of said main strands.
 8. The mesh structureof claim 1, wherein the ratio of the width of the thickness of said mainstrands is at least 5:1, as measured at the narrowest parts of said mainstrands.
 9. The mesh structure of claim 1, wherein the ratio of thewidth to the thickness of said main strands is at least 20:1, asmeasured at the narrowest parts of said main strands.
 10. The meshstructure of claim 1, bonded to another mesh structure of claim 1,thereby forming a laminate comprising a first mesh structure and asecond mesh structure, said main strands of said first mesh structureextending generally at right angles to said main strands of said secondmesh structure.